mineral
Likely kyanite crystal
Kyanite, Al₂SiO₅
AI-generated identification · may be incorrectA slender blue-gray, bladed crystal with vitreous to pearly luster; Mohs hardness is strongly variable (about 4.5–5 along the blade and 6.5–7 across it), with good lengthwise cleavage and triclinic crystals. The image is small and does not permit definitive identification.
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Physical properties
A slender blue-gray, bladed crystal with vitreous to pearly luster; Mohs hardness is strongly variable (about 4.5–5 along the blade and 6.5–7 across it), with good lengthwise cleavage and triclinic crystals. The image is small and does not permit definitive identification.
Formation & geological history
Kyanite forms during regional metamorphism of aluminum-rich rocks, commonly schist and gneiss, under moderate-to-high pressure; specimens may be Paleozoic or older depending on locality. It commonly occurs with quartz, mica, garnet, and staurolite.
Uses & applications
Used chiefly as a refractory and ceramic raw material; attractive blue crystals are collected and occasionally cut as gemstones, though they are brittle.
Geological facts
Its extreme directional hardness is a classic diagnostic feature. A blue, flattened, fibrous blade can resemble sillimanite, cyanite-like tourmaline, or blue-colored quartz.
Field identification & locations
Common localities include Nepal, Brazil, Switzerland, Kenya, and the United States (Virginia, Georgia, and Colorado). Confirm with hardness tests, cleavage, crystal shape, and ideally specific gravity or Raman/XRF analysis.
